Technical Field
This invention relates in general to chainsaw guide bars for wood harvesting and relates in particular to a detachable and replaceable chainsaw guide bar nose assembly or attachment for fitment to a chainsaw guide bar body and which, when in operation, receives a supply of lubricating fluid from the guide bar body and/or chain and directs it into the chainsaw guide bar nose assembly and hence to moving parts subject to frictional wear via lubricant (or lubricating) conveying (or flow/delivering/supply) channels (e.g., grooves) of special configuration formed within the nose side plate of the nose assembly.
Description of the Prior Art
Chainsaw guide bars are commonly fitted with a detachable nose assembly which incorporates a toothed idler sprocket rotatably mounted about a fixedly disposed central bearing member by means of a bearing race interposed between the sprocket and the fixed bearing which is secured between a pair of nose side plates.
Chainsaw guide bars are provided with a peripheral groove. This groove constrains the movement of the saw chain and also provides a means to convey lubricant from lubrication holes at the end of the bar mounted on the chainsaw or harvester machine to all other areas on the periphery of the guide bar. This groove also allows lubricant to be conveyed to the saw chain, providing lubrication to the moving parts on the saw chain. The lubrication can travel towards the nose of the guide bar, either by travelling along the bottom of the bar groove or by becoming attached to the saw chain itself. The lubricant, after travelling to the nose of the bar has no positive means to lubricate the bearing in the nose assembly itself. The lubricant that makes it to the sprocket is thrown off by the centrifugal forces as the sprocket is rotated by the chain.